1. Field of the Invention
This invention relates generally to the field of paving roadways and specifically to a pivoting edger for a paver.
2. Description of Related Art
In laying asphalt pavement roadways and the like, it is widespread practice to employ so-called floating screed paving machines. These machines include a tractor-like main frame having an engine for propulsion and for material distributing functions. Typically, there is a material receiving hopper at the front of the paver arranged to receive hot asphalt material from a truck as the paving machine advances along the roadbed. Slat conveyors or the like are provided to convey the material from the hopper, at the front of the machine, toward the floating screed, at the back of the machine. Immediately in front of the screed, there is typically provided a distributing auger, which receives the raw asphalt material from the slat conveyor and conveys it laterally so as to distribute the material along the front edge of the screed. As the machine advances along the prepared roadbed, the raw asphalt material flows under the screed, which levels, smoothes and compacts it to provide a continuous, level pavement mat.
Each end of the screed has an edger which is a vertical plate extending forwardly from the screed at a right angle to the screed. A horizontal wear plate extends along the bottom edge of the vertical plate and is vertically adjustable by a pair of hand jacks. The edger keeps paving material from spilling out past the end of the screed and forms a clean edge of the paving material.
In a typical floating screed asphalt paver, the screed is attached to a pair of forwardly extending tow arms which engage the paver frame at their forward extremities. These tow arms are also connected to the paver frame by hydraulic or other actuators arranged to adjust the vertical position of the tow arm extremities in relation to the paver frame. By effecting proper control over the position of the tow arm forward extremities, the screed is maintained in relation to a reference plane or a reference element substantially independent of the irregular vertical motions of the paver frame itself. Thus, it is possible to cause the floating screed to lay a pavement mat which is smooth and level in relation to the underlying base surface.
To control the position of the screed, it has proven advantageous to utilize a mobile reference beam, which is carried along with the paver as it moves over the roadway base surface. Many pavers use a moving reference beam arrangement in connection with the laying of wide pavement mats, utilizing a combination of reference beams, one being towed ahead of the screed and auger, supported on the roadway base grade, and the other being towed behind the screed and auger, supported on the just-laid asphalt mat. The system generally includes leading and trailing reference beams of rigid structure, independently supported by a plurality of yieldable supports. The leading reference beam is supported by a plurality of shoes or plates, while the trailing beam is supported by a pair of shoes.
When paving a road, the paving material is distributed relatively evenly along the base surface. However, when the paver encounters a surface, such as a road or driveway which intersects the road being paved, additional paving material is required to form a smooth transition with the intersecting road or driveway. Typically, the extra material is obtained by slowing the paver, and raising the wear plate to allow material to flow under the edger. The material is distributed with hand rakes to the desired width and depth.
In addition to the paver just described, pavers used to widen an existing road have been described. U.S. Pat. No. 3,636,831 to Davin shows a road widening paver with a blade that swings out from the side of the paver. The blade has an adjustable edger at its end. U.S. Pat. No. 4,861,191 to Smith shows a road widening paver with blades that swing out from opposite sides of the paver. Each blade has an adjustable edger at its end.
It would be advantageous to have a floating screed paver which paves a base surface and also permits paving material to be distributed over a desired width beyond the end of the floating screed at selected locations without adversely affecting paver operation. The device should be adaptable to a floating screed paver capable of paving a full roadway in a known manner. The device should blend the paving material with an intersecting road, whether that road is sloped toward or away from the road being paved. Remote control of the device would be a desirable feature.